Rear timing chain stretch and failure (123d)
Attaches to N47S at engine level · Engine · carried by 4 variants across 4 chassis
Overview
Rear timing chain stretch and failure (123d) is a common fault recorded against N47S at engine level, typically from 90–180k km. It shows up as a rattle or whirr from the back of the engine, worst on cold start; at worst the chain skips or snaps and bends valves. Where it's documented, the repair runs €1,500–€2,500 (engine-out chain job at a specialist, costs dated 2026-07), and it can be partly checked before you buy. 4 variants across 4 chassis in this database inherit it.
What happens
Symptom. A rattle or whirr from the back of the engine, worst on cold start; at worst the chain skips or snaps and bends valves.
Cause. Like every N47, the 123d mounts its timing chain at the gearbox end of the engine, where a stretched chain and worn guides can fail and take the engine with them. The higher output works the chain harder.
How to check it
Cold start
Listen at cold start for a rear-of-engine rattle, and treat any car without documented chain work as needing it. On a 123d the repair is a large fraction of the value, so proof matters.
You get one. If the engine is warm when you arrive, come back another day.
Every variant that carries this
| Variant | Chassis | Body | Years | Risk | Good buy | Cost as % of good buy |
|---|---|---|---|---|---|---|
| 123d N47S | E87 | hatchback | 2007–2011 | R4 | €6,450 | 31% |
| 123d N47S | E81 | hatchback | 2007–2012 | R4 | €5,750 | 35% |
| 123d N47S | E82 | coupe | 2007–2013 | R4 | €6,650 | 30% |
| 123d N47S | E88 | convertible | 2008–2013 | R4 | €6,950 | 29% |
The last column is the point. The same repair is an inconvenience on one variant and a reason to scrap the car on another. A failure costing a quarter of the vehicle's value changes the purchase decision regardless of how rare it is.